Patients receiving therapy with the T101, 9.2.27 or anti-idiotype monoclonal antibodies are being examined to assess localization and retention of the monoclonal antibody on the tumor, the pharmacokinetics of the infused antibody, and the immune response of the recipient to the antibody. These studies have demonstrated the ability of these monoclonal antibodies to reach tumor cells in various tissue locations and, with the appropriate dose and schedule of administration, to coat most or all of the tumor cells. Administration of the T101 antibody is accompanied by antigen modulation which, although undesirable for therapy with monoclonal antibody alone, may provide an efficient means for internalization of immunoconjugates of monoclonal antibodies with drugs, toxins or isotopes. As a part of this project, in vitro studies of antigenic modulation and procedures by which it can be enhanced or inhibited are underway to complement our clinical trials.